rain falling from a tall weather system drags with it cold air (a
downdraft)
, which splashes out upon hitting the ground just as paint would if poured from a paint tin
. this splashing is the gusts of wind that blast you prior to the coming of a storm
. of course
, that cold air is not running into empty spac
e; there is a layer of warm air hanging at ground level which is violently forced up out of the way by the rushing cold gusts
. those two differently heated layers rub along each other
, cooling the moisture contained in the warm layer and causing it to condense
. the product of this condensation is called a shelf cloud.
i became interested in this after being bowled over by the closing images from
this sequence of photographs.
here are some other amazing shelf cloud shots:
this next one is really quite astonishing
. the photographer—one mr Anthony Cornelius—must have been brav
e; i’d have run for my life from that
monster 
. the website he posts on is worth a
visit.
… and the last shelf is explored a little more in
this time lapse footage
. check out how it just goes on and on to the right of the frame ther
e! here’s an
account of the storm
, wherein the author styles it a “People Chaser Derecho”
, which among other things makes me feel like i just spun off an old Big Bopper 7
8 :-O :-O :-O
